Normally, automatic couplers used on rapid transit railway equipment, in addition to effecting coupling and uncoupling operations between adjacent cars, also effect connecting and disconnecting operations of the train electrical circuitry and various fluid pressure or pneumatic lines of the train. When uncoupling, it is desirable to disconnect the electrical circuitry and close off the fluid pressure lines before the actual uncoupling of the cars occurs. The circuitry is thus protected from being damaged and fluid pressure is prevented from escaping when separation of the cars occurs. In some of the presently known couplers, self-closing valves are provided in the coupler heads in the fluid pressure connections which are opened and closed automatically and mechanically by coupling and uncoupling action, respectively. These couplers may also be provided with multi-contact blocks in each head for closing and opening the electrical circuitry automatically and mechanically during coupling and uncoupling operation, respectively. During uncoupling it is desirable to open the contacts ahead of the separating action of the coupler heads in order to minimize damage from arcing.
In other known couplers the above described valve and contact actions may be accomplished but by separate actuating mechanism which do not assure that the operations occur in the desired sequential order.